Optical imaging of neural function in gastropod molluscs

Snails and certain other molluscs have been studied extensively as models for understanding fundamental principles of neurophysiology and the neural bases of behaviour. However, work to date has focused almost exclusively on central neurons in major ganglia of the adult. The small, scattered cells in the peripheral nervous system and the entire larval nervous system of such molluscs have proven to be nearly completely resistant to analysis using standard electrophysiological techniques. Thus, we have little idea of how the numerous peripheral cells contribute to the function of the well defined central circuitry, nor how that circuitry develops. There is also little idea of how the neural circuitry and behaviour evolve, although many molluscs, including commercially important species (e.g., scallops, mussels), are now known to have similar peripheral and larval nervous systems to the more well studied model species. Our laboratory is a global leader in providing comparative descriptions of the detailed morphology of both the peripheral and larval nervous systems of molluscs, and modern advances now allow for application of our well developed anatomical techniques to understanding the underlying physiology within these preparations. In this proposal we request an imaging system which permits the high-speed recording of low-intensity optical signals from voltage- and calcium- sensitive dyes within living nervous systems. Dye-loading techniques have already been developed and candidate classes of neurons identified for first analysis. Thus, we are poised to make rapid, high impact advances by establishing a unique facility in the world for the analysis of neural activity in the larval and peripheral nervous systems of molluscs. Once established, these techniques should also be generalizable to similar other applications, including the study of other marine larvae.